Astronomers using the NASA/ESA/CSA James Webb Space Telescope detected a population of 64 brown dwarf candidates with masses ranging from 50 to 84 Jupiter masses in the star cluster NGC 602.
This image of NGC 602 includes data from Webb's NIRCam (near-infrared camera) and MIRI (mid-infrared instrument) instruments. Image credits: NASA / ESA / CSA / Webb / P. Zeidler / E. Sabbi / A. Nota / M. Zamani, ESA & Webb.
NGC602 is a very young star cluster, about 200,000 light-years away in the constellation Hydra, about 2 to 3 million years old.
Also known as ESO 29-43, this star resides in the wings of the Small Magellanic Cloud.
NGC 602's local environment closely resembles that of the early Universe, with very low abundances of elements heavier than hydrogen and helium.
The presence of dark clouds of dense dust and the fact that the cluster is rich in ionized gas also suggests the presence of an ongoing star formation process.
Together with the associated HII region N90, which contains clouds of ionized atomic hydrogen, this cluster provides a rare opportunity to examine star formation scenarios under conditions dramatically different from those in the solar neighborhood.
Using Webb, Dr. Peter Zeidler and his colleagues at AURA and ESA were able to detect 64 brown dwarf candidates in NGC 602. This is the first rich population of brown dwarfs to exist outside the Milky Way.
“It is possible to detect objects at such great distances only with incredible sensitivity and spatial resolution in the right wavelength range,” Dr. Zeidler said.
“This has never been possible and will remain impossible from the ground for the foreseeable future.”
“So far, about 3,000 brown dwarfs are known, and they all live in our galaxy,” said Dr. Elena Mangiavakas, also from AURA and ESA.
“This discovery highlights the ability to use both Hubble and Webb to study young star clusters,” said Dr. Antonella Nota, executive director of the International Space Science Institute.
“Hubble showed that NGC 602 hosts very young, low-mass stars, but only Webb can conclusively confirm the extent and significance of substellar mass formation in this cluster. Hubble and Webb are an amazingly powerful telescope duo!”
“Our results are very consistent with the theory that the mass distribution of objects below the hydrogen burning limit is simply a continuation of the stellar distribution,” Dr. Zeidler said.
“They seem to form the same way, they just haven't accumulated enough mass to become full stars.”
NSF astronomer Dr. Elena Sabbi said, “Studying the newly discovered metal-poor young brown dwarfs in NGC 602 will shed light on how stars and planets formed under the harsh conditions in the early universe. We are getting closer to uncovering the secrets of this.” NOIRLab, University of Arizona, Space Telescope Science Institute.
“These are the first substellar objects outside the Milky Way,” Manjavakas said.
“We need to be prepared for new breakthrough discoveries in these new objects.”
of result will appear in astrophysical journal.
_____
peter zeidler others. 2024. A candidate for a subsolar metallic brown dwarf is discovered in the Small Magellanic Cloud. APJ 975, 18; doi: 10.3847/1538-4357/ad779e
Source: www.sci.news
